An eight hour stand off with police at a California veterans’ home ended with four people dead including the gunman who is believed to have taken his own life.
Police discovered the bodies at the Veterans Home of California-Yountville, which treats veterans for post-traumatic stress disorder, following a suspected hostage situation.
The gunman, identified as Albert Wong, was a 36-year-old patient at the centre.
He is thought to have slipped into a leaving party on the compound at non-profit treatment programme Pathway Home mid-morning Friday.
Authorities described workers inside the building as hostages throughout the day, although it is unclear how long they were held alive for.
Police said shots had been fired as Wong entered the party and they had been unable to make contact with him before the four bodies were found later that evening.
The victims have now been identified as Pathway Home employees Christine Loeber, 48, Jennifer Golick, 42, and clinical psychologist for the San Francisco Department of Veterans Affairs Jennifer Gonzalez, 29.
California Highway Patrol Assistant Chief Chris Childs said it was "far too early to say” if Wong had chosen his victims at random as investigators were yet to establish his motive.
"This is a tragic piece of news, one we were really hoping we would not have to come before the public to give,” he said.
Pathway Home paid tribute to the workers who died in the shooting, in a statement.
"These brave women were accomplished professionals who dedicated their careers to serving our nation's veterans, working closely with those in the greatest need of attention after deployments in Iraq and Afghanistan," the organisation said.
California Governor Jerry Brown said flags would be flown at half-staff at the capitol and said that he and his wife "are deeply saddened by the horrible violence."
Yvette Bennett, a wound-care supply worker who supplies the veterans’ centre, was turned back when she tried to deliver what she called urgently needed medical supplies for two patients inside.
She said the facility was “the most placid, calm, serene place,” she had worked and had asked a doctor earlier this week: "What's your magic here?"
"And then 48 hours later this happens."
Yountville is situated some 50 miles north of San Francisco and has a population of around 3,000, a third of whom live on the grounds of the veterans’ home.
In the heart of California’s Napa Valley wine country, it is home to several vineyards as well as two Michelin-starred restaurants.
The Veterans Home of California was established in the town in 1884 and houses around 1,200 elderly and disabled former soldiers who served in conflicts from the Second World War to the Iraq War.
Additional reporting by Associated Press
